I have been getting a strange boost issue lately, from cold start up it seems fine under full throttle but once it is at operating temperature and you put your foot into it at about
15-17psi it has a rapid backfire/stumbling noise and the power is greatly decreased. Boost leak? that is my first guess anyways, but if it is why doesn't it stumble at 10-14psi?
I replaced the stock FPR with an aftermarket adjustable one set at 35-36ish for now (which is stock to my knowledge) which seemed to help a bit. this
fall/winter the engines coming out and it will be getting a full go threw, all seals replaced and while it's out I am thinking about putting in a range roller
set-up, 3" DP And ill port and polish the Exhaust Manifold as well as the upper and lower intake and use a whole lot of engine degreaser to clean it all up.
Anyways if anyone has any ideas or suggestions or has dealt with a problem like this before i would like to hear from you, cause this is g me off.
I bet you're blowing out the spark on your plugs. I had the same issue at one point.
Check your gap.
I had a similar effect when my intake tubing between the VAM and the turbo was sucking shut.
check vam hose
check plug gap
set your fuel pressure to 40 with the vac referance off.
Go on a drive with the fuel pressure gauge conneceted aznd verify F/P rises 1:1 with boost.
Thanks for the help guys especially sleeper. I have a video of what it sounds like under power from the outside after i pull away from doing a burnout, you can here it in second gear then i let off fast, its a strange sound but sounds like I might need to bump my fuel pressure up and check my spark plug gap.
heres video.
http://www.youtube.com/watch?v=q0QT7Pyme6g
Yea, thats def not the vam hose... I'd check those gaps..
sounds lean